With Season 6 of “The Walking Dead” in full swing and a pretty major cliffhanger leaving a bad taste in fans’ mouths, all eyes are on the supersize fourth episode of the hit zombie drama, "He's Not Here." With the previews teasing the long-awaited origin story of Morgan (Lennie James), many fans may require a refresher on what viewers have learned about the character so far.

Morgan is the second character introduced on “The Walking Dead.” He makes his first appearance in the pilot episode when he saves Rick Grimes (Andrew Lincoln) from his very first walker and has the privilege of explaining the zombie apocalypse both to the series’ principal star and viewers. However, Morgan stays behind to train his son Duane (Adrian Kali Turner) while Rick ventures off to find his family, hijack a farm and set up residence in a prison. While all that is going on, Morgan apparently deals with tragedy on top of tragedy, which he explains to Rick in Season 3, episode 12, “Clear.”

In the pilot, Morgan reveals that he was unable to save his wife, Jenny (Keisha Tillis), in the initial outbreak. She was bitten, the fever took her, and he was forced to watch her turn. For a while, the last image anyone had of Morgan was of him aiming a rifle at the walker that used to be his wife. Unfortunately, he was unable to pull the trigger. It was an artful moment that demonstrated to the viewer that people would have to do unimaginable things to those they loved in order to survive. However, for Morgan it turned out to be so much more.

The Walking Dead "The Walking Dead" episode 1 introduced Morgan (Lennie James, not pictured) and the story of his wife, Jenny (Keisha Tillis, center). Season 6, episode 4 plans to finally reveal what happened to Morgan after the death of his family. Photo: AMC/Scott Garfield

When Rick reconnects with Morgan in “Clear” he’s a mere shell of the calm and well-reasoned man we met in Season 1. Instead, he’s a literal crazy person who doesn’t seem to recognize Rick and has been spending his time hunting and trapping walkers in an attempt to clear the area of the infestation. Once Rick gets him to recognize him, Morgan reveals that the worst has happened. He went out on a supply run only to return to find his walker wife had cornered Duane. The boy hesitated to kill his mom for a split second and was killed because of it. Morgan says he killed them both, this time without a moment’s hesitation. Clearly the trauma made him snap and, when we leave him in “Clear,” he’s simply continuing his mission to hunt, kill and burn every walker he sees. How, then, does he return in Season 5 as a bo staff-trained zen warrior?

It looks like that question will be directly addressed in the 90-minute episode, according to a clip, which sees Morgan in his same attire from “Clear,” hunting with an assault rifle instead of a bo. Since returning to the group and joining the Alexandria colony, Morgan has revealed that he studied how to fight with his now signature weapon sometime between “Clear” and his return. He mentions an unknown man he met taught him the basics, which he clearly mastered.

Morgan’s skills and new, less-crazed outlook on life have been a mystery since he showed up in the final episode of Season 5. While it looks like fans are about to finally have the show’s longest-running plotline resolved, the story could lead to terrible consequences for our intrepid heroes in the present day. Some comments that Morgan made in the “Clear” episode have led many comic book fans to speculate that he carries with him knowledge of a nefarious group of survivors that might cause the group more trouble than the Wolves already have.

When Rick first encounters the deranged version of Morgan, he tells him that there’s no way he’s Rick Grimes and that he’s just another person wearing dead men’s faces. While this sounds like the inane ramblings of a guilt-addled lunatic, it may be some deep foreshadowing for a villain from the comic series. Without going into too much potential spoiler detail, the group is called the Whisperers, and they have found a way to survive the zombie apocalypse in a way that’s eerily similar to what Morgan described.

Unfortunately, fans will have to wait until Morgan’s origins are explored in more detail during Season 6, episode 4 of “The Walking Dead” when it premieres Nov. 1.